Performance Study of Ash Slurry Disposal System of a Thermal Power Station

Centrifugal slurry pumps are the most commonly used pumps used for ash slurry disposal system. The present work is based on study of properties of ash contents present in slurry at different concentration of water. The performance of centrifugal slurry disposal pump would be studied at different concentration of ash present in slurry. The amount of ash content in the mixture of coal- ash and water will be varied to see the effect on the performance of ash disposal system in centrifugal pumps. A thermal power station is a power plant in which the prime mover is steam driven. Large amount of ash is produced in central stations, as much as 10 to 20% of the total quantity of coal burnt in a day. Theoretically whole of the ash from the furnace should get deposited in the ash hoppers, but actually from 5 to 40% of it leaves with the outgoing gases. Ash handling comprises of operations such as removing the ash from the furnace ash hoppers, conveying this ash to storage by means of conveyors and disposal of the stored ash. To handle huge amounts of ash per day, mechanical means are employed. The ash handling and disposal system can work continuously (1). Discharge pressure and the abrasive wear are the two key factors for selecting an ash disposal pump. The centrifugal pump works on the principle of forced vortex flow. The rise in pressure head at any point of the rotating liquid is proportional to the square of tangential velocity of the liquid. Thus at the outlet of the impeller, the rise in pressure head will be more and the liquid will be discharged at the outlet with high pressure head. Hence the liquid can be lifted to a high level. Centrifugal Pumps are used for Transportation of Slurry because of its Simplicity of design, easy installation, low maintenance, lower weight, handles suspensions and slurry easily. Centrifugal slurry pumps are best suited for short distances and for in-plant slurry pipe line systems. These pumps are used for over 97% of all short distance slurry pipelines.